The purification of waste water has experienced considerable technical development in recent years. While various treatments utilize different processes, the utilization of chlorine to oxidize the contaminants and bacteria is perhaps the best known and most advanced method of treatment. While ozone has many advantages over chlorine in the treatment of waste water, the utilization of ozone has been limited because it is expensive to generate and must be used in relatively large quantities. The instant invention is directed to a method and apparatus for increasing the efficiency of an ozone-based oxidation system.